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WATER is an integral part of the manufacture of pulp, paper, and paperboard. It plays a critical role in virtually every step of paper making, from the processing of pulp to the carrying of fibers to the paper-making machines. Water also is used to generate steam for power generation and for process use. Most of the water requirements are met by surface supplies (rivers and lakes) with the remainder from wells. Some mills also use city water. Since water-quality requirements for steam generation are well documented, this article will focus directly on process-water requirements and problems.

Section (1) gives a survey of paper-making processes and of their power requirements. Special problems of power generation and distribution, and the protective system adopted against overload and short-circuits, are dealt with in Section(2). Drives for paper-machine auxiliaries, with a description of the ?plural starter? system, are detailed in Section(3). Section(4) deals with paper-machine drives, and gives a brief description of leading types. High-accuracy speed control for paper machines is the subject of Section (5). Section (6) gives information in regard to drives for ?finishing? machines, supercalenders, reeling machines and slitters. Finally, Section (7) deals with miscellaneous applications of electricity in the paper mill.

The first part of this paper reviews the progress made in improving the aerodynamic design of axial flow turbines and describes experience at the National Gas Turbine Establishment (N.G.T.E.) in the use of some of these techniques. The second part of the paper discusses the present status of internal air cooling for turbine blades and shows how some of the design techniques established for aero-engines might be exploited in the field of power generation.

Twenty-four years ago the first industrial gas-turbine unit, a Brown Boveri 4000 kW set installed by the City of Neuchâtel in Switzerland, started a new era of power generation. This new type of prime mover has since been widely introduced and generally accepted. It serves as base-load and as peaking plant. The fuels used range from natural and blast-furnace gases to diesel, crude, and heavy fuel oils. Extensive experience of running has accumulated in all applications which has permitted the analysis of the operating performance of the gas turbine. The paper reports on the performance of some characteristic gas-turbine installations that are representative of the different applications and fuels. In addition to providing interesting information on the general performance of the gas turbine, the experience gained under various conditions has also permitted the discovery, understanding, and control of special design problems not previously recognized. The more important of those discovered in recent years are discussed and corrective measures are explained.

Power generation for civilian aircraft can only be considered in terms of what kind of flying people will want to do in the 2nd century because the weight and cost of the fuel which will be best are dependent on how much people can afford to pay, how large and how fast they want the planes to be and what the world's total aircraft fuel consumption will be in relation to the world's total supplies of various fuels.The predictable primary power sources of the second century are the fossil chemical fuels, oil and natural gas, the nuclear fuels (fission and fusion) and solar energy.

Quantitative and qualitative information on domestic refuse as a fuel is given; attention is drawn to its heterogeneous nature and variability in properties both short term and long term. Modern equipment for incineration is referred to and particular reference is made to the associated aspects of flue gas attemperation and chimney emissions. Potential usage of the heat produced by incineration in boiler or other heat exchanging plant is discussed in terms of functional considerations and economics; in Appendix 1 a more detailed study of the economics of generation of electricity is made. It is concluded that there is no prima facie case for heat recuperation of all incinerators and in the present circumstances each case must be examined on its merits.

Diesels used by the Central Electricity Generating Board as prime movers for supplying stand-by or emergency auxiliary supplies of electricity require to have a high level of reliability and availability. These are the important features rather than the production of cheap electricity. When used exclusively for generating electricity for the grid system, their use is restricted because of limitations in MW output potential. Those in use must (1) produce cheap electricity, (2) assist in the continuity of supply, and (3) have peak-lopping facilities in certain applications. The major operational cost is fuel, and four fuels are considered; these range from 35 s to 3500 s fuel oils. Diesel maintenance costs can be substantial and methods of reducing these are reviewed in depth. Continuity of supplies of electricity into the National Grid and for local loads is critical. The electrical, mechanical, and chemical aids used to maintain diesel reliability are discussed.

This paper gives the results of a survey conducted by the Power Distribution System Subcommittee of the Pulp and Paper Industry Committee of the IEEE Industry Applications Society. Its purpose was twofold, 1) to explore utility/mill relaying and electrical tie practices and, 2) to explore and devise safe and expeditious operation practices in reenergizing a circuit after a primary or medium voltage feeder breaker tripout has occurred.

ON THIS and the following 2 pages appear all remaining discussions submitted for publication, and approved by the technical committees, on papers presented at the 1937 AIEE winter convention, New York, N. Y., January 25–29. Discussions of papers presented at the sessions on general power applications, vibration and balance, communication and research, power transmission, education, power generation and electrical machinery, instruments and measurements, insulation co-ordination, and lightning protective equipment at the 1937 AIEE summer convention, Milwaukee, Wis., June 21–25, now are being reviewed by the technical committees, and will appear in ELECTRICAL ENGINEERING as they are released for publication.

Hybrid-integrated millimeter-wave sources at 30, 60, and 100 GHz have been built using a novel oscillator configuration. The new structure features a planar microstrip circuit in a conducting channel with an IMPATT diode which is inserted into the side wall of the channel. RF efficiencies of 5 percent at an output power of a quarter-watt CW have been measured both at 30 and 60 GHz. The output power at 100 GHz is 25 mW with an efficiency of 2 percent. The oscillators can be readily tuned over a 10-percent bandwidth.

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Since the original use of solar cells for electrical power generation in space, the state of the art in solar-cell arrays has experienced some significant advances. The solar cell itself has been improved in many ways. These improvements have increased silicon solar-cell efficiencies from roughly 5% to 11% in space sunlight. Material improvements have been made in silicon which have enhanced the resistance of silicon solar cells to particle radiation. The methods used to connect cells into modules as a building block for constructing large arrays have been improved also. New methods in the soldering of cells into modules have decreased the degradation of the cells resulting from handling and soldering. In addition, the successful fabrication of cells into modules has made possible the matching of cells by modules rather than by single cells. The methods used to mount the modules to the supporting structure have been improved by using better techniques and bonding agents. With the above advances, sun-oriented arrays have been built which approach 10 w/ft2 and 10 w/lb when operated in near Earth space (with no particle radiation damage). With further research and development, the watts per square foot, watts per pound, radiation resistance, and cost of solar-cell arrays may he optimized further.

Comments by F.O. Blackwell, H.A. Lardner, and B.J. Arnold. The Redlands plant is the first three-phase power transmission plant in the United States. It had at first two 250 k.w. 2500 volt generators, operated by wheels under a 300 foot head, alnd a seven mile transmission; synchronous motors were used. Later, ahead of 800 feet was developed, and two 450 k.w. 11,000 volt machines were operated on a 30-mile transruission. This plant was connected in parallel with the Santa Ana plant, which supplied a transmission line 90 miles long to Los Angeles. The plant described in the pnaper operates under a head cf 2,000 feet and has a capacity of 4,000 hp, using the same water as the former plant. The generators are of low-voltage, tlle line pressure is 33,000 volts, and feeds into the same transmission lines to Los Angeles. The Los Angeles Edison Company controls seven power stations, located at points as far apart as 100 miles - all feeding the same transmission system, and operating practically as one station; they are now developing a new plant on the Kern River, of a capacity of 20,000 h.p. to operate at 60,000 vclts and transmuit 150 miles to Los Angeles. Thus the history of this system embodies the entire development cf hydro-electric transmission in this country.

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This short paper, written as part of a symposium, outlines the status of a gas turbine development, briefly describes the two types of power plant resulting from this development to date, and outlines their applications.

The demands for electrical power generation capacity have increased significantly in recent years. This paper covers the manufacturing of uranium dioxide nuclear fuel (UO2), for use in commercial nuclear reactors presently used for electric power generation. It explains in detail, the manufacturing and processing steps associated with the conversion of uranium hexafluoride gas into UO2; the compacting of UO2 pellets and the assembly of fuel rods and fuel assemblies. This paper can be described as a walking tour through a typical nuclear fuel fabrication plant.

This paper discusses observations on electric steam and hot-water boilers. The increased popularity of both steam and hot water generation by electricity is readily apparent. The advantages of this type of heat generation lend themselves to many current applications in the heating, ventilating, and air conditioning field. Sizes of boilers have been increasing through the years, with no apparent end in sight due to the accelerated development of the electrode boiler, which will be covered in detail in the second part of the paper. As compared to the resistance type of boiler, this latter design permits economical projection into much larger boiler sizes. Electric boiler installation is relatively simple since there is no concern with chimneys or fuel storage. Often the boiler room can be eliminated and the mechanical equipment room serve as the required space. Electric boiler operation can be automated to the point where an operator is virtually unnecessary with the many control options available today. Integration of the boiler into heat recovery and solar energy systems has also accelerated the growth of this product. As might be expected, due to the simplicity of boiler construction and accessories, electric boiler maintenance is at a minimum. However, certain areas of additional control must be exercised since unique problems can develop with electric steam and hot water generation. The paper is illustrated with pictures of actual installations and case histories covering the gamut of specification, installation, and successful operation.

This paper is written to present the point of view of the practical operating engineer to whom ``reactive power'' is something that he has to generate and deliver to his customers much as he does ordinary or real power. It happens that this kind of reactive power is the kind which causes the current to lag behind the voltage when it happens to be flowing in the same direction in the circuit as the ``active'' power. However, when it happens to be flowing in the direction opposite to that of the active power (which, in a transmission system is just about as likely to happen), it makes the total current in the circuit appear to lead the voltage and deceives the technician who observes this phenomenon into thinking that a different kind of reactive power (viz., leading reactive power) is flowing in the same direction as the active power. The paper presents an interpretation of such observations in terms of the one kind of reactive power with which the practical operation and control of power systems has to deal and points out the parallelism between active and reactive power in their operating aspects. It also presents an unorthodox metering technique for keeping track of the flow of reactive power in a complicated power transmission network which greatly clarifies and simplifies the problem of dispatching reactive power in such a system; such dispatching being necessary to obtain maximum transmission system capacity and efficiency as well as for system voltage control.

The object of this paper is to point out that the existing methods of measuring power when applied to unbalanced three-phase systems are not equitable for symmetrical polyphase machinery. On the other hand, unsymmetrical loads on polyphase systems are not sufficiently penalized for the trouble which they create in the system. It is first of all shown that a symmetrical generator cannot deliver power except through the balanced components of current. The unbalanced currents are capable of resolution into two balanced systems of currents, one of which is of the same phase sequence as the generator e. m. f., and the other component is of reversed or negative phase sequence. The generator cannot deliver power through the medium of this latter component of the currents, because the instantaneous product of the generated voltage and these currents in the three phases is always zero. However, the volt-ampere product per phase is of great significance, because it is a measure of the effect of the current unbalance on the system. The generator therefore delivers power only through the medium of the positive phase sequence currents. Any power that appears in the system through the negative phase sequence currents is positive phase sequence power which has been supplied by the generator and degraded through unbalanced loads and fed back to the system in the form of negative phase sequence power. This power is always additional loss in all rotating machines on the system, and with the present method of charging, the consumer having symmetrical machines is charged with this additional power, which serves him no useful purpose but reduces the output of his machine and decreases his load power factor. In the paper it is proposed that the positive phase sequence power output only be measured, and the power charges be made on the basis of this measurement. It is further proposed that the unbalanced k-va., which is the product of the positive sequence voltage and the negative sequence current be measured either by means of a negative sequence ammeter, indicating or recording, or a k-va. meter, and a charge made for the amount of unbalance. The user of symmetrical polyphase rotating machinery should then be given a lower rate, based on the estimated cost of unbalance, and the consumer having unbalanced loads should be charged directly for the amount of unbalance he creates, or else should have his positive phase sequence power rate increased, based upon the estimated cost of unbalance. It is pointed out that the unbalanced kv-a. is a factor of the same order of importance as reactive kv-a. and in any system subject to unbalanced conditions this factor should be considered and the unbalanced factor, as well as the power factor, should be measured. The unbalanced factor is the ratio of the negative phase sequence kv-a. and the positive phase sequence kv-a., the former being obtained by taking the product of the positive phase sequence voltage and the negative phase sequence current. Devices for measuring these quantities are being developed and the outfit for making these measurements will be no more complicated than the present existing measurement devices. In fact the tendency is towards greater simplicity. In presenting this subject the author has no intention of suggesting how rates should be made, but merely wishes to point out what factors enter into the question of equitable rates when the polyphase system is subject to unbalance.

The paper opens with the statement that Great Britain is dependent almost entirely upon coal for the production of electricity, the amount of water-power available being comparatively small. This being so, the inauguration of the “grid” transmission system and the co-ordination of power production afford favourable conditions for combining the latter with the distillation of coal.The development of the Babcock process of low-temperature coal distillation is briefly described. So far as the authors are aware, this is the only process of its kind developed in Great Britain. It is suggested that the electric power plant of the future will take in coal as its raw material, but will deliver, in addition to electricity, motor spirit, fuel oil, creosote, pitch and other derivatives of coal tar. A discussion of the actual results obtained from the coal distillation plant at Dunston-on-Tyne follows.The plant was designed for the production of an ideal power-station fuel, low in volatiles and therefore smokeless, and for the recovery of the more valuable by-products consistent with the production of such a fuel. The broad result obtained is that 16 gallons of tar oils and ¾ton of semi-coke are produced from 1 ton of Northumberland small coal. The paper goes on to discuss the potentialities of low-temperature tar and it is explained that investigation of this aspect of coal distillation is by no means complete. The field of research is said to be one which presents wide possibilities.In conclusion it is claimed that a new situation exists in which a practical process of coal distillation has been evolved in conjunction with the generation of electricity, and that as a result a definite step forward in the better utilization of our most valuable national asset, namely coal, is now due.A full description of the coal distillation plant at Dunston-on-Tyne is given as an Appendix to the paper.

This paper reviews the work carried out at the Atomic Energy Research Establishment (AERE) since 1963 in connection with the development of isotope-powered thermoelectric generators, known as RIPPLEs. It outlines the criteria considered for the selection of strontium 90 as the radioisotope, the design of the generators, the choice of material for the biological shield, and the development of the thermal insulation. It briefly discusses the voltage conversion system employed and states safety design considerations. The paper concludes by discussing the effect of efficiency on the cost of generators and shows typical costs curves.

The paper presents the results of overload and short-circuit tests made about two years ago upon some synchronous converters in circuit with auxiliary reactors. Two entirely separate sets of tests upon two synchronous converters of widely different operating characteristics are described. In the one case the reactor is in the a-c. circuit and in the other in the d-c. circuit; yet in each it may be called, and in fact is, a protective reactor. In presenting this original information the author, with a view to indicating its commercial application and hoping to provoke discussion, has endeavored to divide synchronous converter installations in a general way into classes with respect to the need or desirability of employing protective reactance, and also with respect to the general design or type of the reactor to be employed. In order to do this, synchronous converter installations are divided into a few general classes with respect to the character and exactions of the service conditions under which they are required to operate. The paper was written shortly after the tests were made, but although much has been learned or written about protective reactors since that date, the author believes nothing has transpired to affect the value of these tests or to make it necessary to change the form in which it was originally intended to present them.

In this paper a brief review is given of the basic principles of MHD power generation and its current status. The remainder of the paper will discuss the problem of obtaining the level of gas ionization required for MHD generation.

This paper deals with experiences in connection with the starting up and the initial operation of a steam-electric generating station, located at Baltimore, consisting of large cross-drum, sectional header, water tube boilers fitted with water cooled furnaces which are fired by pulverized coal. The plant operates at 450-lb. pressure with 725 deg. temperature steam, the turbines being fitted for four-stage bleeding. All auxiliaries are motor driven, the power being supplied either from direct-connected auxiliary generators, or from the main station bus bars through step-down transformers. This paper attempts to describe the major difficulties that were encountered in placing the plant in operation and outline the methods used in their elimination.

This paper discusses the interconnection between three of the leading power supply companies in the eastern part of the country, the Philadelphia Electric Co., the Pennsylvania Power & Light Co., and the Public Service Electric & Gas Co. It outlines the physical aspects of the tie-in between the companies which is a 220-kv. ring of high-load capacity, triangular in shape with sides respectively 49 mi., 82 mi., and 77 mi. long. The advantages of the interconnection are enumerated as well as some of the operating problems. Preliminary to the discussion of the interconnection the paper discusses the Conowingo hydroelectric project, an important factor in the interconnection scheme. The plant has an initial installation of 280,000 ky-a. in generators.

During the past few years, stability characteristics of systems using long lines have been discussed at considerable length, but not so much attention has been given to the characteristics of the load. This paper shows that power limits may be reached with very short lines and certain classes of load. The characteristics of several classes of load, such as motors of various kinds with constant shaft output, variable impedance loads (synchronous converters for railways), constant impedance, and miscellaneous combinations, are discussed as they affect the stability of the generator. The criterions for the stability of an alternator as developed by this paper are ``short-circuit ratio,'' saturation, power factor of the load, and character of the load. A series of curves and a formula for the minimum allowable value of short-circuit ratio as a function of saturation and power factor are proposed for general purpose alternators which may be called upon to deliver power to any of the various classes of load. These curves are derived from characteristic curves of typical machines. It is not intended that these curves shall be used for generators which supply power over long transmission lines, as the characteristics of these lines may require considerably higher values of short-circuit ratio, and the generator must be specially designed to meet the individual requirements.

At the mid-winter convention of the A. I. E. E. in February, 1924, the writer presented a paper on the maximum instantaneous values of the currents delivered by alternating-current generators under different short-circuit conditions. A summarized table was given for the maximum values of the short-circuit currents for different winding combinations of an ideal generator on the basis of a constant field flux, and that the short-circuit occurs at the instant the axis of the field winding coincides with the axis of the particular portion of the armature winding under consideration. In the present paper, a similar analysis is given for the magnitude and variation of magnitude of the short-circuit currents during the transient period, that is, during the time the currents vary from the maximum to the sustained values.

1. In Appendix I, a computational procedure for the solution of economic load dispatching problems is developed. The equations are in generalized form in that the variables at any entering node to the network may be either the vector potential above ground or else the vector current entering the electric network. Generating station losses as well as electric network losses are included. 2. An example is presented in the body of the paper which involves three generators and two loads. The equations presented in Appendix I are adapted to fit this specific problem. In so doing, it was elected to replace the generalized variables by voltages above ground at all entering nodes on the electric network. 3. Numerical results for the example are presented in Appendix II. 4. The method presented in this paper requires the solution of simultaneous algebraicequations, some of which involve nonlinearities. Experience with the example suggests: (a) A Taylor's series expansion technique is applicable; (b) The selection of a starting point, in the multidimensional domain of the variables, that will lie near the point representing the actual solution, is of vital importance in assuring the rapid convergence of the calculations; (c) The selection of such a point may be achieved by computing a common incremental rate Pa? at the generating stations while neglecting the electric network losses, and then computing the electric potentials plus the Lagrange multipliers while assuming equal but unspecified incremental power rates for the generators.

This paper describes the salient features of a magnetron which attained by the spring of 1953 a peak power of up to 10 megawatts at 10 microseconds pulse duration and 17 kilowatts average power. There was little previous knowledge or experience available for guidance at the time (1947) the development was started. Among the most important problems which had to be solved were: 1) The establishment of reliable criteria of π-mode stability as guides for high power magnetron design; 2) the development of a microwave window of sufficient bandwidth for lower order mode loading and which would permit operation of the tube at full power in air at atmospheric pressure; 3) the development of a cathode capable of withstanding high back bombardment power with reasonable life; 4) the development of methods for fabricating a large magnetron; 5) the elimination of voltage breakdown in various parts of the magnetron; 6) the development of a modulator to produce and measure 2 to 10-microsecond pulses up to 100 kilovolts and up to 400 amperes; and 7) the development of a calorimetric load of low thermal capacity for testing the magnetron at full power. This paper is intended to assist the designers of magnetrons and systems to better appreciate: 1) The problems involved in the simultaneous attainment of multimegawatt power levels at long pulse durations, long wavelength and high duty; 2) what has been accomplished in this regime with magnetrons; and 3) that the experimental material given in the discussion is representative of an advance in magnetron art and not necessarily a limitation of what can be expected by way of performance from the pulsed magnetron.

This paper considers the problem of devising modulation techniques that allow a large number of earth stations to use, simultaneously, a satellite repeater with the transfer characteristics of a wide-band hard-limiting amplifier. Four distinct classes of modulation techniques and their singular properties are described. Three important design considerations are discussed: repeater bandwidth and power sharing, network timing, and operational considerations. The paper provides a framework for further study of the multiple access problem. The hard-limiting repeater is shown to accommodate a wide variety of signal designs. No single class of multiple-access modulation techniques is found to be uniformly best in satisfying all needs of the diverse networks which can use communication satellites.

In recent years developments in the application of transmission loss formulas to the economic dispatch of power systems have been very rapid. The purpose of this paper is to describe the method used to apply the loss formula principle to the calculation of transmission losses in the economic dispatch of power on the Tennessee Valley Authority (TVA) system. The paper presents the results of a study of the accuracy obtained by a selected number of methods when applied to the TVA system. It also includes the application of a rapid and systematic method of checking the validity of each set of loss formula coefficients before being put into use in the hourly economic scheduling program.

The use of power factor corrective devices on distribution circuits is justified, under certain conditions, by rather substantial savings in investment charges and by a reduction in the power losses of the system. The object of the present paper is to develop a practical working formula for calculating the most economical corrected power factor for a distribution circuit. Most economical conditions are assumed when the total of such annual circuit costs as are directly affected by a change in power factor, is a minimum. The usual methods for computing separately, the saving in I2 R losses and the decrease in investment charges due to power factor improvement, are inadequate. Particularly in the design of new circuits and extensions has the need for a more accurate method for calculating optimum power factor and conductor sizes been expressed.2 Since these equations were originally worked out, two other solutions for the most economical corrected power-factor angle have been published, each having been obtained independently of the other. Menjelou3 obtained his formula in the form: ? sin ? = 1 - s tan ? in which ? is the power-factor angle and ? and s are constants computed from the circuit costs. Stevenson4 obtained a similar expression: sin ? = ? - ? tan ? the difference lying in the constants to be evaluated. The equation developed in this paper reduces to the simple form.

This paper discusses superconductivity and the related Meissner effect in relation to electric power generators. Both effects have been suggested for use in improving electrical devices through reduction of friction and other losses, weight, and/or volume. The study described in this paper is analytic and preliminary in nature and without test data, but indicates that large superconductive power generators offer a good potential for future application.

This paper surveys British progress, over a five-year period since an earlier paper [1], in meeting the steeply rising demand for electricity. During this period EHV cables, having over twice the conductor section and power transfer capabilities previously used, have been designed and manufactured.

This paper describes the communication system which has been installed to serve the power plant at Conowingo, Maryland, and its associated transmission line. The important features to be considered in designing a telephone system for a power plant are pointed out. The types of telephone switchboard and telephone instruments chosen in this case to meet the special requirements of the generating station, together with the layout and cabling arrangement, are outlined. The paper also discusses the possible ways of providing for the needs of the load dispatcher and the plan adopted at Conowingo; the facilities provided the patrolmen for calling from points along the transmission line; the connection from the private branch exchange to the general telephone system; and the special electrical protection installed on the long lines leaving the power house.

Over the last few years, considerable effort has been devoted to employing the plasma state in applications as widely differing as microwave and optical frequency devices; power generation by thermonuclear fusion; magnetohydrodynamic (MHD) and thermionic energy conversion, and the propulsion of spacecraft. In some of these areas intense activity still continues, and encouraging progress is being made. In others the results have been disappointing, and after an initial period of enthusiasm interest has waned. This paper is restricted to such an area, and reviews microwave plasma device research. A few years ago it seemed that a new and useful range of components, including phase shifters, beam-plasma amplifiers, and harmonic generators, might be developed. After a great deal of work, there is still a dearth of serious commercial plasma competitors to existing vacuum tube and solid-state devices. The paper discusses some of the obstacles to microwave plasma device development that have been encountered along the way, and some of the paths that have been taken to circumvent them. It is concluded that the present disappointing situation is likely to persist unless a major breakthrough is made in production of a simple quiescent plasma source, or there is a departure from the present device concepts.

It is the purpose of this paper to deal especially with the employment of electric power, derived from hydroelectric systems of distribution, for the operation of textile mills. It is impossible in a paper of this kind to go very fully into detail, and no attempt will be made to discuss the forms of drives, kind of motors or, in fact, any other technical details, since any one of the more important ones would require a special paper to do it justice.

The paper covers a number of thermal or calorimeter tests which were made on a 55,000-kva. generator at the Queenston generating station of the Hydro-Electric Power Commission of Ontario. The objects of the tests were to determine stray-load losses on short circuit and under rated load, and to obtain some information regarding the accuracy of this type of test. The paper includes descriptions of the methods followed and of the actual tests made. The details of the calculations are given in the appendix. The results of the tests show that the stray-load losses can be determined with fair accuracy by this method on large units when an enclosed system of ventilation is used. They also seem to show that the difference between the stray-load losses under load conditions and under short-circuit conditions is slight, and that a test under load conditions is justified only when a very accurate determination of the losses is required. For most purposes, a test under short-circuit conditions seems to be sufficient.

Load-sensing governors have become a commercial reality since the 1939-45 war, but their use appears to have been restricted largely to applications where the load is an electrical machine. The need to reduce transient speed errors in order to maintain constant frequency during large load changes in electricity generation and computer applications is well recognized. This paper reports on improvements made in the performance of speed governors, by the addition of load sensing, when applied to normally aspirated reciprocating internal combustion engines. Its aim is to stimulate interest amongst engineers seeking improvement in the transient performance of various kinds of governed machinery. A simple linearized theoretical treatment of the load-sensing control system, which predicts, approximately, the behaviour of a real system, is presented in this paper. Experimental tests, carried out on automotive 4-stroke petrol and diesel engines, indicated that load changes could not occur with absolutely zero temporary droop, and that the test arrangement was more stable at high loads. Comparison of transient performance with and without load sensing showed that the 10 per cent temporary droops, required by B.S. 649 and B.S. 3109, was never achieved without load sensing. With load sensing, an improvement by a factor of 4 was recorded, reducing the temporary droop below the requirements of the specifications.

The paper considers the application and cost of electricity in this country, with the economical use of raw fuel. It is pointed out that the development of low prices per kilowatt-hour to encourage an improved load factor has had no regard for economy in the use of coal, a matter which is now vital to the nation, and that heat units are of greater importance than artificial monetary values. The paper covers a wide field, with the object of provoking consideration of all aspects of the use of electricity, and generally no attempt has been made to develop closely detailed arguments. The application of the electric drive in industry is criticized. Tables are provided to indicate the wasteful use of motors, and proposals are made for effecting the necessary improvements. The integration of electrical generation with other forms of energy is briefly considered. The possibility of providing a cheap supply of energy for electrolytic and electrochemical processes from a coal-fired station is considered, and the author concludes that in certain circumstances the cost could be brought within the limits regarded as essential by those industries.

At the Atlantic City TIMS-ORSA-AIIE meeting (November 8–10, 1972), the College on the Practice of Management Science sponsored its second open competition for the best paper describing a completed, real application of management science. The prize winners were Messrs. Elden D. Thomas and Donald P. Coveleski, for their paper. People in government agencies, electric utilities, industrial concerns, and even average citizens are becoming painfully aware of the problems involved in putting nuclear energy to work in the power generation industry. These difficulties have been particularly significant to Babcock & Wilcox which has been a leader in energy conversion technology through the years. As a result, the company has been working for several years to contribute to the solution of these problems.